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New insights into the substrate specificities of proton‐coupled oligopeptide transporters from E. coli by a pH sensitive assay
Author(s) -
Prabhala Bala K.,
Aduri Nanda G.,
Jensen Johanne M.,
Ernst Heidi A.,
Iram Nida,
Rahman Moazur,
Mirza Osman
Publication year - 2014
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2014.01.004
Subject(s) - oligopeptide , escherichia coli , electrochemical gradient , substrate (aquarium) , tripeptide , transporter , chemistry , biochemistry , substrate specificity , efflux , symporter , biophysics , peptide , biology , membrane , enzyme , ecology , gene
Proton‐coupled oligopeptide transporters (POTs) are secondary active transporters that facilitate di‐ and tripeptide uptake by coupling it to an inward directed proton electrochemical gradient. Here the substrate specificities of Escherichia coli POTs YdgR, YhiP and YjdL were investigated by means of a label free transport assay using the hydrophilic pH sensitive dye pyranine and POT overexpressing E. coli cells. The results confirm and extend the functional knowledge on E. coli POTs. In contrast to previous assumptions, alanine and trialanine appears to be substrates of YjdL, albeit poor compared to dipeptides. Similarly tetraalanine apparently is a substrate of both YdgR and YhiP.